Peerless Series GM GM-07
The Peerless Series GM GM-07 is a current semi-commercial cast-iron gas boiler firing 342 MBH for 275 MBH gross output and a 239 MBH net water rating at 80.3% thermal efficiency, in a natural-draft chimney package sized for single, multiple or modular installations.
Key figures
- Max input
- —
- Max CSA output
- —
- AFUE
- —
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Peerless Series GM GM-07 in practice
The Series GM GM-07 is one of the four current gas-fired cast-iron sizes in Peerless' Series GM line, positioned by the official page for large residences and multiple or modular installations. Its in-page rating row prints 342 MBH input, 275 MBH gross output and a 239 MBH net water rating (1.15 allowance), at 80.3% thermal efficiency with 82.5% combustion efficiency.
The size measures 25-3/4" deep × 26-1/4" wide × 35-1/4" high with a 10" vent connector, and is fully packaged as an atmospheric boiler for venting into a conventional chimney; the line supports higher-pressure applications requiring up to a 100 PSIG relief valve and pairs with the Peerless Partner indirect water heater as a FLEX-HEAT system.
Boilers.ca records the printed row for the GM-07; no official Canadian-sales statement was found, so canadianStatus stays 'unknown', and gas, combustion and venting work belongs with a licensed contractor against the Series GM or GM-e installation manual.
Best suited to
- 342-MBH-class large-residential or light-commercial loads
- Multiple or modular boiler arrangements vented into a conventional chimney
- FLEX-HEAT systems pairing the boiler with a Peerless Partner indirect water heater
Applicability and support
- Model number
- GM-07
- Canadian availability
- unknown
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Peerless Boilers. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 342 MBH | Input per the in-page Series GM ratings table; the table also prints the metric input column. |
| Output | ||
| Gross output | 275 MBH | Footnote 1 of the in-page table: output is heating capacity for models below 300 MBH input and gross output at or above 300 MBH. |
| Net water rating | 239 MBH | Net water rating based on an allowance of 1.15 per the in-page table. |
| Efficiency | ||
| Thermal efficiency | 80.3 % | Thermal efficiency 80.3% with 82.5% combustion efficiency per the in-page table; no AFUE row is printed for this size. |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | |
| Venting and air | ||
| Vent connector | 10" | Vent size (F) per the in-page dimensions table; natural-draft chimney venting with a built-in draft hood and vent safety switch. |
| Physical and connections | ||
| Dimensions (A × B × C) | 25-3/4" × 26-1/4" × 35-1/4" | Jacket depth (A) × jacket width (B) × jacket height (C) per the in-page dimensions table. |
| Operating limits and other | ||
| Fuel | Natural gas or LP gas | Gas-Fired (Natural or LP) per the product page. |
| Control | Spark pilot ignition | Spark-pilot ignition per the product page; the GM-e manual documents the GM-e-05 to GM-e-07 sizes. |
Manuals
- Series GM Installation, Operation & Maintenance Manual (GM8065 R18, 12/25)GM8065 R18 · 2025-12
- Series GM-e Installation, Operation & Maintenance Manual (GM8099 R1, 3/24)GM8099 R1 · 2024-03
- Catalog Literature — Series GM, CUT-GM R5 (8/25)CUT-GM R5 · 2025-08
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the Series GM GM-07 ratings?
342 MBH input, 275 MBH gross output and a 239 MBH net water rating at 80.3% thermal efficiency (82.5% combustion efficiency) per the in-page ratings table.
Does the Series GM GM-07 need a chimney?
Yes — the Series GM is a natural-draft atmospheric boiler designed for conventional chimney venting in single, multiple or modular installations.
Can Series GM boilers be installed in modular banks?
Yes — the official page describes single, multiple or modular installations, with up to a 100 PSIG relief valve for higher-pressure applications.
Questions about the Peerless Series GM GM-07?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Peerless Boilers — Series GM product page (ratings and dimensions tables) · accessed September 9, 2026
- Series GM Installation, Operation & Maintenance Manual, GM8065 R18 (12/25) (PDF) · GM8065 R18 · accessed September 9, 2026
- Series GM-e Installation, Operation & Maintenance Manual, GM8099 R1 (3/24) (PDF) · GM8099 R1 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.